feat: scale the shell to the room's television

A 32" panel a few feet from the children and a 65" set across a hall want the same design at different sizes. UI_SCALE in device.conf now sets that, and nobody has to edit CSS or source to tune a room. The stylesheet and the notification config become templates carrying measurement tokens. classroom-dock resolves the stylesheet in memory at startup; classroom-notifications resolves the notification config into the session's runtime directory and execs mako on it, so the process is still just mako and everything that looks for it by name still finds it. Neither template is rewritten on disk, so an update cannot lose a room's setting and a room cannot drift from the packaged design. Dock height and the reserved strip, corner radii, padding, button size, spacing, every icon, the clock and its inset, and the notification geometry all follow the scale. Colours, translucency and the hairline borders do not: those are the design, not the size. At UI_SCALE=1.0 the rendered stylesheet is byte-identical to the one the shell used before any of this existed, which is the property worth keeping. Values outside 0.8 to 1.5 are clamped and anything that is not a number falls back to 1.0, so a typo in device.conf cannot produce an unusable classroom. Device configuration moves into a shared module, since the dock and the notification daemon now have to agree about what a setting means. Co-Authored-By: Claude Opus 5 <[email protected]>
2026-09-04 21:33:09 -05:00
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+# UI scale
+
+Every classroom gets the same design at a size that suits its TV. A 32"
+panel a few feet from the children and a 65" set across a hall want
+different sizes of the same dock, not different docks.
+
+## Changing it
+
+Edit `/etc/ekklesia-classroom/device.conf` on that endpoint:
+
+```
+UI_SCALE=1.25
+```
+
+Then restart the classroom shell:
+
+```
+sudo systemctl restart getty@tty1
+```
+
+That ends the session and the autologin brings it straight back with the
+new size. A reboot does the same thing. Nothing else needs touching, and
+no CSS or source file is ever edited to change a room's size.
+
+## Values
+
+| UI_SCALE | Roughly |
+| --- | --- |
+| 0.8 | Small or close-up panel |
+| 1.0 | Default. 1080p classroom TV, 32–50" |
+| 1.25 | Large room, or a set viewed from further back |
+| 1.5 | 65"+ |
+
+Anything outside 0.8–1.5 is clamped to that range, and anything that is
+not a number at all falls back to 1.0, so a typo in device.conf cannot
+produce an unusable shell.
+
+## What it scales
+
+- Dock height, and the reserved strip at the bottom of the screen
+- Dock corner radius, padding and the spacing between buttons
+- Button size, padding and corner radius
+- Every dock icon
+- Clock text size, padding, corner radius and its inset from the edge
+- Notification width, height, padding, margin, corner radius, text size
+  and icon size
+
+Colours, translucency and the hairline borders do not scale: those are
+the design, not the size. At `UI_SCALE=1.0` the rendered stylesheet is
+byte-identical to the one the shell used before scaling existed.
+
+## How it works
+
+`/etc/ekklesia-classroom/dock/style.css.in` and
+`/etc/ekklesia-classroom/mako/config.in` are templates carrying
+measurement tokens. `classroom-dock` resolves the stylesheet in memory at
+startup; `classroom-notifications` resolves the notification config into
+the session's runtime directory and hands it to mako. Neither template is
+ever rewritten on disk, so an update cannot lose a room's setting and a
+room's setting cannot drift from the packaged design.